Method and apparatus for diluting and mixing chemical solution for agriculture

ABSTRACT

A chemical solution such as farm chemicals, pesticides or liquid fertilizers is injected and mixed under pressure at a predetermined rate into pressurized water and automatically controlled when spraying of the diluted and mixed chemical solution is discontinued or restarted, by means of an apparatus comprising a pressurized water conduit provided with an orifice and a connecting part successively in a water flow passage, a forward end of the water conduit being connected to a spraying means, a pressurized chemical solution conduit provided with a stop valve, a pressure regulator valve and an orifice successively in a solution conduit, a forward end of the solution conduit being connected with the connecting part of the pressurized water conduit, a pressure regulator mechanism capable of detecting pressures at upstream sides of the orifices of the pressurized water conduit and the pressurized chemical solution conduit, respectively, and equilibrating the pressures through a pressure regulator valve synchronized with a controlling device, and a mechanism capable of detecting flow rates through pressure differences between the upstream and downstream of the respective orifices of the pressurized water conduit and the pressurized chemical solution conduit by means of a flow rate checking means, and synchronizing the pressure differences with opening or closing of the stop valve through a valve-operating monitor.

United States Patent [1 1 Mihara Nov. 6, 1973 1 METHOD AND APPARATUS FORDILUTING AND MIXING CHEMICAL SOLUTION FOR AGRICULTURE [75] Inventor:Kazuyasu Mihara, Niihama, Japan [73] Assignee: Sumitomo ChemicalCompany,

Ltd., Osaka, Tokico, Ltd., Kanagawa-ken, both of Japan 22 Filed: Mar.24, 1972 211 Appl. No.: 237,802

2,823,740 2/1958 Morck, Jr.. 239/61 2,265,961 12/1941 Ziebolz 137/1002,657,091 10/1953 Quarles 239/61 3,464,626 9/1969 Stamps et a1. 239/10'3,519,010 7/1970 Helling et a1. -l37/100 3,685,531 8/1972 Byford 137/100X Primary Examiner-Lloyd L. King Assistant Examiner-A. KashnikowAtt0rney--Richard K. Stevens et a1.

MON/ TOR [5 7] ABSTRACT A chemical solution such as farm chemicals,pesticides or liquid fertilizers is injected and mixed under pressure ata predetermined rate into pressurized water and automatically controlledwhen spraying of the diluted and mixed chemical solution is discontinuedor restarted, by means of an apparatus comprising a pressurized waterconduit provided with an orifice and a connecting part successively in awater flow passage, a forward end of the water conduit being connectedto a spraying means, a pressurized chemical solution conduit providedwith a stop valve, a pressure regulator valve and an orificesuccessively in a solution conduit, a forward end of the solutionconduit being connected with the connecting part of the pressurizedwater conduit, a pressure regulator mechanism capable of detectingpressures at upstream sides of the orifices of the pressurized waterconduit and the pressurized chemical solution conduit, respectively, andequilibrating the pressures through a pressure regulator valvesynchronized with a controlling device, and a mechanism capable ofdetecting flow rates through pressure differences between the upstreamand downstream of the respective orifices of the pressurized waterconduit and the pressurized chemical solution conduit by means of a flowrate checking means, and synchronizing the pressure differences withopening or closing of the stop valve through a valve-operating monitor.

8 Claims, 5 Drawing Figures H CONGEVTRA- T/O/V EECTOR PATENTEU 5973SHEET 1 [IF 5 atwm s PAIENTEDNUV 61973 SHEEI a BE 5 (lllln'llllll I.

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u llnlll l SHEET 3 BF 5 F QESQQ PATENTEUNOV 5191s MUQ PAIENTEU 5 I973SHEET 5 [If 5 METHOD AND APPARATUS FOR DllLUTING AND MHXING QHEMICALSOLUTION FOR AGRICULTURE This invention relates to a method and anapparatus for diluting and mixing a chemical solution such as farmchemicals, pesticides, liquid fertilizer, etc. with water to apredetermined proportion.

A large-scale orchard or farm has been recently using a method forspraying an agricultural chemical solution such as farm chemicals,pesticides, liquid fertilizers, etc. by means of a sprinkler, whilemixing and diluting the chemical solution with water to a predeterminedproportion. One of main devices of the so-called agricultural sprinklersystem is an apparatus for diluting and mixing the chemical solutionwith water. The dilution and mixing of such a chemical solution arecarried out by injecting and mixing into a pressurized water conduitgenerally under a wide range of the atmospheric pressure to 15 kg/cm gthe chemical solution at a predetermined rate in proportion to a flowrate of water passing through the conduit.

The present invention provides a method and an apparatus developed fromthese viewpoints and particularly devised as a method and an apparatusfor diluting and mixing a chemical solution for agriculture with water.

For the dilution and mixing of a chemical solution such as farmchemicals, pesticides, liquid fertilizers, etc. for agriculture, it isstrongly desired particularly that the desired concentration of thechemical can be securely maintained within a narrow definite range, theoperation of the apparatus is simple and closely connected to laborsaving, and the operation can be automatically kept to a safety anddesired conditions, even if there is some misoperation.

Now, the present invention will be explained in detail, referring to theaccompanying drawings.

FIGS. 1 to are schematic flow diagrams showing embodiments of thepresent invention.

In FIG. 1, water flows down under pressure from a head tank 1 installedat a definite high level, for example, on a top of hill through aconduit 3, and is led to a liquid-spraying means 15, for example, asprinkler or sprayer through an orifice 4 and a connecting part 5. Atthat time, the water head tank 1 is not always necessary to install atsuch a high level. That is, water can be effectively transferred underpressure by means of a suitable pump from a water tank installed even ata low level. On the other hand, an agricultural chemical solution suchas farm chemicals, pesticides, liquid fertilizers, etc. is transferredfrom a chemical solution feed tank 2 through a conduit 9 under pressureby a pump 13 and led to the connecting part 5 of the pressurized waterconduit 3 through a stop valve 6, for example, electromagnetic valve,pneumatically operated valve, etc., a pressure regulator valve 7 and anorifice 8, and the pressurized chemical solution is injected into thepressurized water through the connecting part 5. A pressure controlvalve 16 provided at a discharge side of the pump 13 is effectivelyutilized to control a dis charge pressure of the pump 13 and stirs thefeed chemical solution in the feed tank 2 at the same time. As the feedchemical solution, a liquid fertilizer and water-soluble pesticides andfarm chemicals are used in a liquid state. Orifices 4 and 8 are providedin the conduits 3 and 9, respectively, and the controller of a pressureregulator valve 7 is used to receive a pressure signal from the upstreamsides of the orifices 4 and 8, and adjust and keep the pressure of thechemical solution in the conduit 9 to the same level of the pressure ofthe water in the conduit. The controller 10 provides a diaphragm, wherethe regulation of pressure is carried out by converting displacements ofthe diaphragm to the degree of opening of valve plug of the pressureregulator valve 7 synchronized with the displacements. That is to say,when the pressure of the chemical solution turns higher than thepressure of the water, the diaphragm of the controller is displacedtowards the water side, and therefore the degree of opening of the valveplug of the pressure regulator valve 7 synchronized with thedisplacement is reduced thereby. The flow rate of the chemical solutionpassing through the valves is throttled, and the pressure of thedownstream side of the pressure regulator valve 7 is lowered. When thepressure of the downstream side of the pressure regulator valve 7 forthe chemical solution turns lower than the pressure of the water in theconduit 3, the valve functions in a reversed manner, whereby thepressure regulation can be carried out. This pressure regulationcontinuously functions in a repeated manner until the pressure of thewater in the conduit 3 at the upstreamside of the orifice 4 becomesidentical with the pressure of the downstream side of the pressureregulator valve 7 in the feed chemical solution conduit 9.

In FIG. 2, another embodiment is shown, where a function to open orclose the pressurized chemical solution conduit 9 when theliquid-spraying means 15 is used or not is added to the apparatus shownin FIG. 1. That is, as shown in FIG. 2, a flow rate-detecting means 11is provided in the pressurized water conduit 3 to detect a pressuredifference between the upstream side and the downstream side of theorifice 4, that is, the flow rate, and transfer the detected flow rateto a valveoperating monitor 12. A stop valve 6 is provided at theupstream side of the pressure regulator valve 7 in the pressurizedchemical solution conduit 9. As the stop valve 6, an electromagneticvalve, pneumatically operated valve, etc. can be used. Thevalve-operating monitor 12 is connected to said stop valve 6, andtransmits an actuating signal to the stop valve 6 according to a flowrate signal from the flow rate-detecting means 11 When the signal fromthe flow rate-detecting means 11 shows zero, the valve-operating monitor12 transmits a signal to close the valve to the stop valve 6, wherebythe conduit 9 is closed.

That is, when operating valves l5a-15c are closed at the liquid-sprayingmeans 15 and the liquid spraying is discontinued, the flow ratedetecting means 11 detects a zero flow rate and transmits a zero signalto the monitor 12. The monitor 12 immediately transmits a valve closuresignal to the stop valve 6, and the pressurized chemical solutionconduit 9 is automatically closed, whereby a mixing of the chemicalsolution into the pressurized water conduit 3 can be prevented.

Further, when the operating valves l5a-15c are reopened and the liquidspraying is started again, the flow rate-detecting means 11 immediatelytransmits a flow rate signal to the monitor 12, and the stop valve 6 isautomatically opened, whereby the mixing of the chemical solution withwater is started.

In FIG. 3, another embodiment is shown, where a function to close thepressurized chemical solution conduit 9 for an emergency when thereoccurs a disorder in the pressure regulator valve 7 is added to theapparatus as shown in FIG. 2. As shown in FIG. 3, a flow rate-detectingmeans 14 is provided in the pressurized chemical solution conduit 9 todetect a pressure difference between the upstream side and thedownstream side of the orifice 8, that is, a flow rate, and transfer thedetected flow rate to the valve-operating monitor 12.

The monitor 12 receives a flow rate signal from the flow rate-detectingmeans 14, and when the valve of the flow rate signal exceeds thepredetermined one or the mixing ratio exceeds a predetermined proportionbased on the flow rate of water detected by the flow rate-detectingmeans 11, the monitor 12 transmits a valve closure signal to the stopvalve 6 to close the pressurized chemical solution conduit 9.

That is, when the chemical solution flows in excess of the predeterminedflow rate owing to a disorder of the pressure regulator valve 7, etc. ora mixing ratio exceeds the predetermined proportion, the stop valve isautomatically closed immediately, and an inconvenience due to thefurther mixing of the chemical solution can be prevented thereby.

In FIG. 4, another embodiment is shown where a function to close thepressurized chemical solution conduit for an emergency by other meansthan that of the embodiment of FIG. 3 is added to the embodiment ofFIG. 1. That is, as shown in FIG. 4, a concentration detecting means 14which transfers a signal to the monitor 12 is provided at any desiredposition from the downstream side of the connecting part at the joint oftwo conduits 3 and 9 up to the liquid-spraying means 15. The signal fromsaid means 14 is transferred to the valve-operating monitor 12, and whenthe concentration of the mixed solution exceeds a predetermined value,the monitor 12 transmits a valve closure signal to the stop valve 6according to the signal from the concentration-detecting means 14.According to this system, such a complicated operation as the comparisonwith the flow rate of other conduit by the monitor 12 as shown in FlG.3, is not necessary.

In FIG. 5, another embodiment is shown, where a function to close theconduit 9 for an emergency, as shown in FIG. 4, is added to theembodiment of FIG. 2. That is, the chemical solution conduit 9 isautomatically opened or closed by a combination of the flowrate-detecting means ii and the monitor 12 according to the use of theliquid-spraying means, and an abnormal mixing of the chemical solutiondue to a disorder of the pressure regulator valve, 7, etc. can beprevented. The mechanism is simpler than that of FIG. 3.,

and has a function to close or open the chemical solution conduit 9according to the state of liquid spraying and close the conduit 9 for anemergency.

As described above, in the present apparatus, a chemical solutionadjusted to a pressure equal to that of the pressurized water can beinjected and mixed under pressure, at a predetermined rate, into thepressurized water passing through a conduit, and at the same timediscontinuation and feeding of the chemical solution can beautomatically controlled when spraying of the agricultural solutiondiluted and mixed with the chemical solution is discontinued orrestarted. Therefore, the dilution of a chemical solution by water canbe always maintained in a constant range and the chemical can be alwaystreated with the safety. Therefore, the present apparatus is mostsuitable for dilution and spraying of farm chemicals, pesticides, liquidfertilizer, etc. for agriculture.

What is claimed is:

1. An apparatus for diluting and mixing a chemical solution foragriculture with water to a predetermined mixing proportion, whichcomprises a water conduit provided with an orifice and a connecting partsuccessively in a water flow passage, a chemical solution conduitprovided with a pressure regulator valve and an orifice successively ina chemical solution flow passage and connected to the connecting part ofthe water conduit, a liquid-spraying means connected to a forward end ofthe connecting part of the water conduit, a controller to regulate adegree of opening of the pressure regulator valve in correspondence witha pressure at an upstream side of the orifices, a stop valve at anupstream side of said pressure regulator valve in the chemical solutionconduit, a flow rate-detecting means in said water conduit to detect apressure difference between the upstream side and the downstream side ofthe orifice, and a valve-operating monitor to receive a signal from theflow rate-detecting means to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquid-spraying means.

2. An apparatus according to claim 1, wherein a flow rate-detectingmeans is provided in the chemical solution conduit to detect a pressuredifference between an upstream side and a downstream side of the orificeand transfer a flow rate signal to the valve-operating monitor, and thestop valve is automatically closed when the chemical solution flowsthrough the conduit at a mixing ratio in excess of a predetermined one,based on a flow rate of water.

3. A method for diluting and mixing a chemical solution for agriculturewith water to a predetermined mixing proportion, which comprises passingwater through a water conduit provided with an orifice having a flowrate-detecting means to detect a pressure difference between theupstream side and the downstream side of the orifice, and a connectingpart successively in a water flow passage to a liquid-spraying meansconnected to a forward end of the connecting part of the water conduit,while passing a chemical solution through a chemical solution conduitprovided with a pressure regulator valve having a stop valve provided atan upstream side of the pressure regulator valve and an orificesuccessively in a chemical solution flow passage and connected to theconnecting part of the water conduit, and mixing the water with thechemical solution at the connecting part under control of a controllerto regulate the degree of opening of the pressure regulator valve incorrespondence with a pressure at an upstream side of the orifices whilehaving a valveoperating monitor receiving a signal from the flowratedetecting means so as to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquidspraying means.

4.. A method according to claim 3, wherein a flow rate-detecting meansis provided in the chemical solution conduit to detect a pressuredifference between an Lip-stream side and a downstream side of theorifice and transfer a flow rate signal to the valve-operating monitor,and the stop valve is automatically closed when the chemical solutionflows through the conduit at a mixing ratio in excess of a predeterminedone, based on a flow rate of water.

5. An apparatus for diluting and mixing a chemical solution foragriculture with water to a predetermined mixing proportion, whichcomprises a water conduit provided with an orifice and a connecting partsuccessively in a water flow passage, a chemical solution conduitprovided with a pressure regulator valve having a stop valve provided atan upstream side of the pressure regulator valve and an orificesuccessively in a chemical solution flow passage and connected to theconnecting part of the water conduit, a liquid-spraying means connectedto a forward end of the connecting part of the water conduit, acontroller to regulate a degree of opening of the pressure regulatorvalve in correspondence with a pressure at an upstream side of theorifices, a valve-operating monitor which operates the stop valve and aliquid concentration-detecting means at a downstream side of theconnecting part at a joint of the water conduit and the chemicalsolution conduit to transfer a concentration signal to saidvalveoperating monitor, whereby said stop valve is closed when theconcentration of mixed solution exceeds a predetermined one.

6. An apparatus for diluting and mixing a chemical solution foragriculture with water to a predetermined mixing proportion, whichcomprises a water conduit provided with an orifice and a connecting partsuccessively in a water flow passage, a chemical solution conduitprovided with a pressure regulator valve and an orifice successively ina chemical solution flow passage and connected to the connecting part ofthe water conduit, a liquid-spraying means connected to a forward end ofthe connecting part of the water conduit, a controller to regulate adegree of opening of the pressure regulator valve in correspondence witha pressure at an upstream side of the orifices, a stop valve at anupstream side of said pressure regulator valve in the chemical solutionconduit, a flow rate-detecting means in said water conduit to detect apressure difference between the upstream side and the downstream side ofthe orifice, and a valve-operating monitor to receive a signal from theflow rate-detecting means to operate ing proportion, which comprisespassing water through a water conduit provided with an orifice and aconnecting part sucessively in a water flow passage to a liquidsprayingmeans connected to a forward end of the connecting part of the waterconduit, while passing a chemical solution through a chemical solutionconduit provided with a pressure regulator valve having a stop valveprovided at an upsteam side of the pressure regulator valve and anorifice successively in a chemical solution flow passage and connectedto the connecting part of the water conduit, and mixing the water withthe chemical solution at the connecting part under control of acontroller to regulate a degree of opening of the pressure regulatorvalve in correspondence with a pressure at an upstream side of theorifices with a liquid concentration-detecting means at a downstreamside of the connecting part at a joint of the water conduit and thechemical solution conduit transferring a concentration signal to avalve-operating monitor which operates the stop valve whereby the stopvalve is closed when the concentration of mixed solution exceeds apredetermined one.

8. A method for diluting and mixing a chemical solution for agriculturewith water to a predetermined mixing proportion, which comprises passingwater through a water conduit provided with an orifice having a flowrate-detecting means to detect a pressure difference between theupstream side and the downstream side of the orifice, and a connectingpart successively in a water flow passage to a liquid-spraying meansconnected to a forward end of the connecting part of the water conduit,while passing a chemical solution through a chemical solution conduitprovided with a pressure regulator valve having a stop valve provided atan upstream side of the pressure regulator valve and an orificesuccessively in a chemical solution flow passage and connected to theconnecting part of the water conduit, and mixing the water with thechemical solution at the connecting part under control ofa controller toregulate a degree of opening of the pressure regulator valve incorrespondence with a pressure at an upstream side of the orifices whilehaving a valveoperating monitor receiving a signal from the flowratedetecting means so as to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquidspraying means and having a concentration-detecting meansat a downstream side of the connecting part at a joint of the waterconduit and the chemical solution conduit to transfer a concentrationsignal to the valveoperating monitor whereby the stop valve is closedwhen the concentration of mixed solution exceeds a predetermined one.

1. An apparatus for diluting and mixing a chemical solution foragriculture with water to a predetermined mixing proportion, whichcomprises a water conduit provided with an orifice and a connecting partsuccessively in a water flow passage, a chemical solution conduitprovided with a pressure regulator valve and an orifice successively ina chemical solution flow passage and connected to the connecting part ofthe water conduit, a liquidspraying means connected to a forward end ofthe connecting part of the water conduit, a controller to regulate adegree of opening of the pressure regulator valve in correspondence witha pressure at an upstream side of the orifices, a stop valve at anupstream side of said pressure regulator valve in the chemical solutionconduit, a flow rate-detecting means in said water conduit to detect apressure difference between the upstream side and the downstream side ofthe orifice, and a valve-operating monitor to receive a signal from theflow rate-detecting means to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquidspraying means.
 2. An apparatus according to claim 1,wherein a flow rate-detecting means is provided in the chemical solutionconduit to detect a pressure difference between an upstream side and adownstream side of the orifice and transfer a flow rate signal to thevalve-operating monitor, and the stop valve is automatically closed whenthe chemical solution flows through the conduit at a mixing ratio inexcess of a predetermined one, based on a flow rate of water.
 3. Amethod for diluting and mixing a chemical solution for agriculture withwater to a predetermined mixing proportion, which comprises passingwater through a water conduit provided with an orifice having a flowrate-detecting means to detect a pressure difference between theupstream side and the downstream side of the orifice, and a connectingpart successively in a water flow passage to a liquid-spraying meansconnected to a forward end of the connecting part of the water conduit,while passing a chemical solution through a chemical solution conduitprovided with a pressure regulator valve having a stop valve provided atan upstream side of the pressure regulator valve and an orificesuccessively in a chemical solution flow passage and connected to theconnecting part of the water conduit, and mixing the water with thechemical solution at the connecting part under control of a controllerto regulate the degree of opening of the pressure regulator valve incorrespondence with a pressure at an upstream side of the orifices whilehaving a valve-operating monitor receiving a signal from the flowrate-detecting means so as to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquid-spraying means.
 4. A method according to claim 3, whereina flow rate-detecting means is provided in the chemical solution conduitto detect a pressure difference between an up-stream side and adownstream side of the orifice and transfer a flow rate signal to thevalve-operating monitor, and the stop valve is automatically closed whenthe chemical solution flows through the conduit at a mixing ratio inexcess of a predeteRmined one, based on a flow rate of water.
 5. Anapparatus for diluting and mixing a chemical solution for agriculturewith water to a predetermined mixing proportion, which comprises a waterconduit provided with an orifice and a connecting part successively in awater flow passage, a chemical solution conduit provided with a pressureregulator valve having a stop valve provided at an upstream side of thepressure regulator valve and an orifice successively in a chemicalsolution flow passage and connected to the connecting part of the waterconduit, a liquid-spraying means connected to a forward end of theconnecting part of the water conduit, a controller to regulate a degreeof opening of the pressure regulator valve in correspondence with apressure at an upstream side of the orifices, a valve-operating monitorwhich operates the stop valve and a liquid concentration-detecting meansat a downstream side of the connecting part at a joint of the waterconduit and the chemical solution conduit to transfer a concentrationsignal to said valve-operating monitor, whereby said stop valve isclosed when the concentration of mixed solution exceeds a predeterminedone.
 6. An apparatus for diluting and mixing a chemical solution foragriculture with water to a predetermined mixing proportion, whichcomprises a water conduit provided with an orifice and a connecting partsuccessively in a water flow passage, a chemical solution conduitprovided with a pressure regulator valve and an orifice successively ina chemical solution flow passage and connected to the connecting part ofthe water conduit, a liquid-spraying means connected to a forward end ofthe connecting part of the water conduit, a controller to regulate adegree of opening of the pressure regulator valve in correspondence witha pressure at an upstream side of the orifices, a stop valve at anupstream side of said pressure regulator valve in the chemical solutionconduit, a flow rate-detecting means in said water conduit to detect apressure difference between the upstream side and the downstream side ofthe orifice, and a valve-operating monitor to receive a signal from theflow rate-detecting means to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquid-spraying means, concentration-detecting means at adownstream side of the connecting part at a joint of the water conduitand the chemical solution conduit to transfer a concentration signal tothe valve-operating monitor whereby the stop valve is closed when theconcentration of mixed solution exceeds a predetermined one.
 7. A methodfor diluting and mixing a chemical solution for agriculture with waterto a predetermined mixing proportion, which comprises passing waterthrough a water conduit provided with an orifice and a connecting partsucessively in a water flow passage to a liquid-spraying means connectedto a forward end of the connecting part of the water conduit, whilepassing a chemical solution through a chemical solution conduit providedwith a pressure regulator valve having a stop valve provided at anupsteam side of the pressure regulator valve and an orifice successivelyin a chemical solution flow passage and connected to the connecting partof the water conduit, and mixing the water with the chemical solution atthe connecting part under control of a controller to regulate a degreeof opening of the pressure regulator valve in correspondence with apressure at an upstream side of the orifices with a liquidconcentration-detecting means at a downstream side of the connectingpart at a joint of the water conduit and the chemical solution conduittransferring a concentration signal to a valve-operating monitor whichoperates the stop valve whereby the stop valve is closed when theconcentration of mixed solution exceeds a predetermined one.
 8. A methodfor diluting and mixing a chemical solution for agriculture with waterto a predetermined mixing proportion, whiCh comprises passing waterthrough a water conduit provided with an orifice having a flowrate-detecting means to detect a pressure difference between theupstream side and the downstream side of the orifice, and a connectingpart successively in a water flow passage to a liquid-spraying meansconnected to a forward end of the connecting part of the water conduit,while passing a chemical solution through a chemical solution conduitprovided with a pressure regulator valve having a stop valve provided atan upstream side of the pressure regulator valve and an orificesuccessively in a chemical solution flow passage and connected to theconnecting part of the water conduit, and mixing the water with thechemical solution at the connecting part under control of a controllerto regulate a degree of opening of the pressure regulator valve incorrespondence with a pressure at an upstream side of the orifices whilehaving a valve-operating monitor receiving a signal from the flowrate-detecting means so as to operate the stop valve, whereby the stopvalve is automatically closed or opened in correspondence with the useof the liquid-spraying means and having a concentration-detecting meansat a downstream side of the connecting part at a joint of the waterconduit and the chemical solution conduit to transfer a concentrationsignal to the valve-operating monitor whereby the stop valve is closedwhen the concentration of mixed solution exceeds a predetermined one.